Mighty Monad

The NP-231 transfer case on my 92 Wrangler (4.0L, manual tranny) is fubar
and I'm looking for info to help me identify a bolt-on used or rebuilt
replacement. Does anyone know of a site that has a good, detailed breakdown
of the differences among the NP-231J cases so I can identify what Jeep year,
model and motor/tranny combos will directly mount to my rig? There seems to
be a good supply of TJ NP-231 cases at reasonable prices. With the improved,
no-fluid-loss setup on some of these cases, what, if anything, is necessary
to use one of these transfer cases on my YJ?

Although the temptation to upgrade to a flipped Dana 300 or the oh-so-pricey
Atlas II is strong, my wallet is weak and plopping in a used NP-231 is by
far the most cost-effective choice for getting my wounded Jeep back on the
road right now.

Thanks!

Dave